docs: def add_arguments(cls, subparsers, dirs):
          """Argument parser of this module.
          """
          parser = subparsers.add_parser(
              'packet',
              help='Packet Bare Metal',
              formatter_class=lambda prog: argparse.ArgumentDefaultsHelpFormatter(prog, max_help_position=40, width=120))
  
          m = parser.add_argument_group('Mandatory Packet Parameters') # pylint: disable=invalid-name
  
          g = m.add_mutually_exclusive_group(required=False) # pylint: disable=invalid-name
          g.add_argument('-create-demand',
                         action='store_true',
                         help='Create an on demand based bare metal device instance.')
  
          g.add_argument('-create-spot',
                         action='store_true',
                         help='Create a spot price based bare metal device instance.')
  
          g.add_argument('-reboot',
                         nargs='?',
                         const=-1,
                         metavar='n',
                         help='Reboot active instances.')
  
          g.add_argument('-stop',
                         nargs='?',
                         const=-1,
                         metavar='n',
                         help='Stop active instances.')
  
          g.add_argument('-terminate',
                         nargs='?',
                         const=-1,
                         metavar='n',
                         help='Terminate active instances.')
  
          o = parser.add_argument_group('Optional Parameters') # pylint: disable=invalid-name
          o.add_argument('-create-volume',
                         nargs='+',
                         type=str,
                         metavar='s',
                         help='Create storage: <plan> <size> <region> <description>')
  
          o.add_argument('-conf',
                         metavar='path',
                         type=argparse.FileType(),
                         default=os.path.join(dirs.user_config_dir, 'examples', 'packet', 'packet.json'),
                         help='Packet configuration')
  
          o.add_argument('-list-projects',
                         action='store_true',
                         help='List available projects.')
  
          o.add_argument('-list-plans',
                         action='store_true',
                         help='List available plans.')
  
          o.add_argument('-list-operating-systems',
                         action='store_true',
                         help='List available operating systems.')
  
          o.add_argument('-list-spot-prices',
                         action='store_true',
                         help='List spot prices.')
  
          o.add_argument('-list-facilities',
                         action='store_true',
                         help='List available facilities.')
  
          o.add_argument('-list-devices',
                         action='store_true',
                         help='List devices under given project name.')
  
          o.add_argument('-project',
                         metavar='project',
                         type=str,
                         default='fuzzing',
                         help='The project to perform operations on.')
          o.add_argument('-tags',
                         metavar='seq',
                         nargs='+',
                         type=str,
                         help='Tags associated with the instance.')
          o.add_argument('-region',
                         metavar='region',
                         type=str,
                         default='nrt1',
                         help='The facility in which the instance is going to run.')
          o.add_argument('-os',
                         metavar='name',
                         type=str,
                         default='ubuntu_18_04',
                         help='The operating system for the created instance.')
          o.add_argument('-plan',
                         metavar='name',
                         type=str,
                         default='baremetal_0',
                         help='The instance type to run.')
          o.add_argument('-max-spot-price',
                         metavar='#',
                         type=float,
                         default='0.05',
                         help='Max price for spot instances.')
          o.add_argument('-count',
                         metavar='#',
                         type=int,
                         default='1',
                         help='The amount of devices to be spawned.')
          o.add_argument('-only',
                         metavar='k=v',
                         nargs='+',
                         type=str,
                         help='Filter instances by criterias.')
          o.add_argument('-version',
                         action='version',
                         version='%(prog)s {}'.format(cls.VERSION),
                         help=argparse.SUPPRESS)